This invention relates to the field of electric battery powered and electric battery power assisted vehicles, and more specifically to ways to both minimize the loss of energy that results when such vehicles are stopped or slowed down by braking, and to accomplish this with a minimum of mechanical parts and systems. This invention also relates to what might be termed the field of alternative personal transport vehicles, i.e. vehicles other than cars, trucks, vans, and the like. This invention also relates to vehicles that are powered simultaneously by both foot pedals and gasoline or electric motors.
A long-standing need for electric powered vehicles and other alternative personal human transport vehicles has been widely recognized due to the tragedies, problems and difficulties associated with conventional fossil fuel powered vehicles. Upwards of forty thousand Americans are killed each year in traffic accidents, and many more people are injured. Pollution from cars is both an immediate problem in areas of heavy traffic and parking garages, and a regional and global environmental problem due to the regional and global effects of both air pollution and thermal pollution. The transportation system built around conventional gasoline powered cars has additional problems including the high cost of building and maintaining roads and parking facilities, and both personal stress and wasted energy resulting from traffic jams.
The emerging field of electric vehicles may solve or reduce many of these problems. These new vehicles will change the way people think about personal transportation. Many of them are likely to be considerably smaller and lighter then even current compact and subcompact cars. The ability to reduce power and battery capacity requirements to a minimum will be crucial to achieving the full benefit from what may be a shift in coming decades to electric vehicles as the primary personal transportation vehicle.
Conventional cars are stopped by brakes, and these brakes dissipate the vehicle's kinetic energy. Some efforts have been made to reduce or eliminate this dissipation. A German bus uses a flywheel/brake combination, where the application of the brake system drives a flywheel and transforms the linear kinetic energy of the vehicle into rotational kinetic energy that is subsequently used to accelerate the bus. Such a system is both bulky and requires many mechanical parts and for these reasons may not be best suited for small electric vehicles. U.S. Pat. No. 5,680,908 is for an electric powered vehicle that includes the use of a generator, and that specifies the generator is used to recharge batteries when the vehicle is decelerating. However, this invention uses separate devices for motors and generators, and requires the use of a transmission system to increase generator rotation to a speed sufficient to generate electricity. In addition, although the generator is specified to operate when the vehicle is decelerating, no mention is made of the function of the generator as a brake, or of the recovery of kinetic energy that would otherwise be dissipated.